Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃a...Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.展开更多
The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later durin...The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later during the life cycle are related or decoupled.The life stages of first year Pacific cod(Gadus macrocephalus)were tracked over different hatch years and regions to test whether the early life history had a long-lasting effect on subsequent growth.We further explored the contribution of growth in the early and subsequent life history stages to body size at the end of each stage.In addition to the accessory growth centre and the first annual ring,the other two checks on the otolith possibly related to settlement and entering deeper waters were identified in 75 Pacific cod individuals.The direct and indirect relationships among the life history stages was interpreted based on path analysis.The results showed that growth prior to the formation of the accessory growth centre had a significant effect on the absolute growth of the fish before and after settlement and migration to deep water.However,there was no or moderate evidence that early growth affected the body size at each stage,which was mainly regulated by growth during the stage.This study supports the lasting effect of early growth and clarifies that it affects size mainly by indirectly regulating staged growth.Quantifying the phenotype relationships and identifying the internal mechanisms form the basis for assessing population dynamics and understanding the processes behind the changes.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR202102270334)the National Key Research and Development Program of China(No.2020YFD0901004).
文摘Natural nano-hydroxyapatite(HA)was extracted from Pacific cod(Gadus macrocephalus)bone with a thermostable col-lagenolytic protease in the present study.Conditions for the enzymatic reaction were optimized to be 60℃and pH 7.0,and a desir-able extraction efficiency was achieved by using the crude collagenolytic protease.Dynamic light scattering,transmission electron microscopy and energy-dispersive X-ray analysis revealed that nano-HA are anionic spherical(about 110nm)particles mainly com-prised of calcium and phosphorus at an approximate ratio of 5:3.As evaluated with the mouse ex vivo intestinal segments,the extracted nano-HA displayed comparable level of intestinal bioavailability to the positive control CaCl_(2).By treating with inhibitors(NaN3,ami-loride)and low temperature(4℃),clathrin-mediated endocytosis was assumed to involve the intestinal absorption of nano-HA.Over-all,the application of thermostable collagenolytic protease is proved to be a promising alternative method for nano-HA extraction from natural resource with improved ecological and biological value.
基金This work was financially supported by China Scholarship Council(202006330094).
文摘The complex life histories of demersal fishes are artificially separated into multiple stages along with changes in morphology and habitat.It is worth exploring whether the phenotypes expressed earlier and later during the life cycle are related or decoupled.The life stages of first year Pacific cod(Gadus macrocephalus)were tracked over different hatch years and regions to test whether the early life history had a long-lasting effect on subsequent growth.We further explored the contribution of growth in the early and subsequent life history stages to body size at the end of each stage.In addition to the accessory growth centre and the first annual ring,the other two checks on the otolith possibly related to settlement and entering deeper waters were identified in 75 Pacific cod individuals.The direct and indirect relationships among the life history stages was interpreted based on path analysis.The results showed that growth prior to the formation of the accessory growth centre had a significant effect on the absolute growth of the fish before and after settlement and migration to deep water.However,there was no or moderate evidence that early growth affected the body size at each stage,which was mainly regulated by growth during the stage.This study supports the lasting effect of early growth and clarifies that it affects size mainly by indirectly regulating staged growth.Quantifying the phenotype relationships and identifying the internal mechanisms form the basis for assessing population dynamics and understanding the processes behind the changes.
